Draft gear



Nov. '3, l925- W. M. AUSTIN DRAFT GEAR j File'd June 1v, 1920 BY l ATTORNEY lTNESSES.

Patented Nov. 3, 1925.

UNITED ASTATI-:s

y .1,559,540 PATENT 'oFIrl-cfr..u'`

WALTER .Us'rn, er swissvALn, PENNSYLVANIA.

' DRAFT enne.

Application led J'nne 17, 1920. Serial No.1 389,605. i

a friction draft rigging that shall have av maximum friction surface.

Another object of my invention is to proa draft rigging having resilient friction members. Y

Another object of my invention is to provide a draft rigging having means whereby the rise in resistance near vmid stroke shall be limited.

Another object of my invention is to provide a draft rigging, of the above indicated character, that shall have means for assisting in the release of the device when pressure is removed.

A further object of my invention is to provide a rigging. of the above indicated character, .that shall be simple and inexpensive to construct and efficient in its opera. tion. y

In practicing my invention, I provide a housing having a tapered openingtherein in which are disposed two resilient oppo sitely-disposed tapered frictional members having double helicaly engaging surfacc A yoke member is disposed within the frictional members and has a flange thereon that engages the inner ends of the inner frictional member. A spring is disposed between the yoke member and oneend of' the housing. Since the resilient frictional members are split longitudinally and, since their engaging surfaces are helical, when they are forced together, they expand to frictionally engage the surface of the opening in the housing. With this'arrangement. the pressure resistingl relative movement between the housing andthe frictional members may be adjusted to any desired value for various de'ections. Y

In the accompanying drawings, Figure 1 is a sectional view of a draft rigging embodying my invention; Fig. 2is an lelevational view. with parts broken away. of the frictional members shown in Fig. 1, and' Fig. 3 is a diagram illustrati-ng the operation yof the device shown in Fig. 1.

A housing' isvprovided with an opening 2 the wallsr'of which taper from the outer end Bfthereof toi thel innerv end. Twofresilient frictional members 5 and 6 sever-ally have two vhelical engaging surfaces 7 and 8 which engage throughout under all conditions. Themembers''and' are splitand separated at points 9 and 10 and are slightly tapered to conformto the taper of the opening in the housing'l. The apex of the mem# berfis normally disposed adjacent the pointl 1 9 and the apexlkv of the Amember 5l is dis-y posed `-adjacent the point 10; Since the.hel-'- ical surfaces 7 and Sare formed in opposite directions from the apex 11 and also 'from the apex 12xit will be readily seen that when 7 Vthe members 5` and Bare moved toward eachl other Vlongitudinally thesurfaces 7 and 8 will remain in engagement and the divided portions 13 and 14 ofthe member `5k will separate as will also'the vdivided* portionsilv and 16 of the member 6.

A cylindrical yoke 17de-disposed''withinv the members 5 and 6 and has a flange-18 at its inner side yupon which 'the member 5- rests. The yoke 17 is provided with an opening 19V at its outer end through which extendsy the stem 20 of a oatin-g member 21. A vrelatively light spring 22 is disposedbetween1 V'the floating member-.'21 and the Vouter end of vtheyoke 17 anda relatively stiff' springQ is disposed between a lrela tively-movable end'cap 4t of the housing 1 and 'the innerk side of the floating member Q1.` 'The capa is provided with an inwardly extending flange 24 that engages an outwardli7 extending flange 32 on the housing 1. However, thelinner end of the housing 1 may be closed and the spring` Q'Brlisposed between the member 21 and the inner end of theV housing; v f' Y Theouter Ifriction member is provided with an inwardly extendingl flange 33.' A plate member 2f von' the member 2O when the rigging is'released is adapted to be engaged byv and the plate 34 intu'rn engages the flange 33 to assist in the releasing'of the oute friction member from the housing.

If no friction'al`v means were`employed. V

the springs would offer a pressurein oppo'f sition: to their defie'ctio-n substantially as lshown in the straight line 25 in 3 of the drawings.V However, 'it isdesirable to greatly increase theV retarding pressure short-ly after the? retarding force' is applied. That is, when it is desired to 'stop atrain', it

-yoke 17 and is first desired to absorb energy as shown at point 26 of the curve 27 and then to greatly increase the pressure of retardation as is shown at the portion 28. This may be accomplished with my invent-ion.

When pressure is applied between thev outer end of the friction member 6 and the cap 4 the springs 22 and are compressedI until the cap 4 engages the inner end of the housing. The two helicalsurfaces 7 and 3 of the outer frictional member 6 are forced against the corresponding surfaces 7 and 8 of the inner frictional member 5. The member 5 is pressed against the flange 18 of the this pressure is transmitted to the springs. The initial action is almost entirelyspring action, the only friction being between the helical surfaces 7 and 8. Further inward movement causes the inner friction member 5to expand against the inside of the housing by the .wedging action between the surfaces 7 and 8 of the members 5 and 6 and the reaction of the springs 22 andk 23. At this point, shown .on curve 27 in Fig. 3 of the drawings, the pressure increases rapidly for small increases in deflection until the smaller spring 22 has shortened to such an extent that any further deiiection presses directly on the larger spring 23 after which only relatively slight increases in reactions of the gear will be had during the remainder of the stroke..

When both the members 5 and 6 have been expanded until their outer surfaces 29 and 30, respectively, touch the bore 31 of the housing 1, any further inward movement of the member 6 will begin to decrease the circumference of both members 5' and 6 thereby causing the inner friction member 5 to move inwardly at a slightly greater rate than the outer member G does. The result of this is to still more tightly press the friction members outwardly againstv the housing by reason of the-frictional reaction parallel to the helical surfaces. i

When the load on the draft gear is reduced to a value less than the difference between the loads on the two springs 22 and 23, the larger spring 23 will expand further compressing the small spring22` and the member 20 will press against the plate and the plate 34 will press outwardly against i the 33 on the member 6 to assist in withdrawing it from the wedged position in engagement with the inner friction member 5.

As soon as the outer friction member 6 begins to withdraw from its innermost position in the housing 1, the inner member 5 will be'forced outwardlyby the springs 22 and 23 thus lmaintaining contact with theV outer friction member 6 until the springs have reached their full length.

It'wi'll be understood that my invention is not limited to two springs, the relatively movable end cap 4 for the housing or to other features such as the plate 34 as it will operate satisfactorily with one spring, a closed inner end for the housing and without the plate 34. I have found that the device may be adapted to obtain any desired characteristics. l. therefore, do not limit my invention to the specific structures illustrated as.it may be variously modified without departing from the spirit and scope of the invention, as set forth in. the appended claims.

l claim as my invention:

1. A draft gear comprising a housing having a tapered interior bore, two oppositely disposed resilient friction members the engaging surfaces of which have a' large pitch and a resilient member disposed between one end of the housing and the corresponding end of one of the'resilient friction members.

2. A draft gear comprising a housing having a tapered interior `bore, two oppositely disposed resilient friction members having engaging surfaces that Ycooperate when the members are moved inwardly in the housing to cause the members vto expand whereby the outer surfaces thereof frictionally engage the inner surfaces of the housing, and resilient means for restoring the friction members to their initial positions.

3. A draft gear comprising a housing having a slightly tapered opening therein, two oppositely disposed resilient friction members having engaging surfaces of relatively large pitch, and a spring disposed within the resilient friction members between one end having an opening therein, two oppositely disposed resilient'friction members having engaging surfaces of relatively large pitch andv a spring disposedv between one end of the housingand the corresponding end'ofv one of the resilient friction'members.

6. A draft gear comprising a housingl having a slightly tapered opening therein, two oppositely disposed fiexible friction members having engaging surfaces of relatively large pitch, a yoke member disposed within the flexible friction members' andy engaging one end of one of the friction members, and a spring resistance within the yoke member between one end thereoic and the housing.

7. A draft gear comprising a housing having a slightly tapered opening therein,

two oppositclydisposed flexible friction members having engaging surfaces of relatively large pitcln'a yoke member disposed within the flexible friction members and engaging one end of one of the friction members, and resilient means. disposed withf in the yoke member between oneend thereof and the housing..y

8. A draft gear `comprising a housing haring a slightly tapered openingA therein,

two oppositelyl disposed resilient friction members having engaging 'surfaces .0fy rela,- tively large pitch, a yoke member disposed within the friction members and engaging one end ofone of the friction members, and resilient means disposed Within the yoke member between one end thereof and the housing. f s

9. A draft rigging comprising. nous ing having` an inner frictional surface, constantly engaged frictional members cooperating therewith, said frictional members being resilient and having engaging surfaces of relatively large pitch whereby lateral movement thereof expands the same to cause the outer surface thereof to frictional engage the inner frictional surface of the housing, and means for releasingr the frictional members from engagement with the housing.

10. A draft rigging comprising a housing having an opening therein, two resilient frictional members disposed in `the the opening and having helical co-operating edges, a spring and means for connecting the spring between the housing and one end of one of the resilient frictional members.

11. A draft rigging comprising a housing, and two resilient frictional members having helical edges that cooperate to eX- pand the frictional members into frictional engagement with the housing when they are moved into the housing and means for restoring the frictional members to their initial positions.

12. A draft rigging comprising a housing, and two resilient frictional members having helical edges that co-operate to eX- pand the frictional members into frictional engagement with the housing when they are moved into the housing and resilient means for resisting the inward movement of the frictional members. i

13. A draft rigging comprising a housing, and two resilient frictional members having helical edges that co-operate to eX- pand the fric-tional members into frictional engagement with the housing when they are moved into the housing, and a spring for 'resisting the inward movement of the frictional members.

14. A draft rigging comprising a main housing having a tapered opening therein, two oppositely disposed tapered frictional members having `double 'helical cooperating edges, ay cylindrical yoke. member having a flanged inner endengaging the inner end ofy one of the frictional members, a'n'dfa spring between the inner end of: the opening in the housing and the outerpe'ndA ofthe yoke member. f

15. AY draft rigging. comprising a mainl housing having a tapered opening therein, two. oppositely disposed tapered frictional. memberslhaving double helicaly ycofoperatf3V ing edges, .a cylindricalyoke member having a flanged inner end engagingfthefinner end of'y one of kthe frictional. members,v a! floating` member within the yoke, and a.- spring' disposed on each-side of the floating'. member between the ryoke and the housing.

1 6; A k draft rigging Vcomprising a main.. housing, and .twooppositely disPQSed'rS ent tapered frieti onal members -liaying he cal engaging surfaces th at remain in engagement underall conditions. said resilient frictional members being adapted to expand into frictional engagement with the housing.

17. A draft rigging comprising a vmain housing and two constantly engaging resilient frictional members having .means where' by they expand into frictional engagement with the housing when they are forced therein and means for opposing the movement inwardly of the frictional members.

18. A draft rigging comprising a main housing having a. tapered opening therein, two oppositely disposed tapered frictional members having double helical co-operating edges, a cylindrical yoke member having a flanged inner end engaging the inner end of one of the frictional members, a floating member within the yoke, a spring disposed on each side of the floating member, and means whereby the floating' member assists in the release of the frictional members when the springs expand.

19. A draft rigging comprising a main housing having a slightly tapered bore, two oppositely disposed resilient tapered frictional members having constantly engaged surfaces whereby the resilient members eX- pand into frictional engagement with theA tapered bore of the housing when they are forced therein, and means for restoring the frictional members to their initial positions.

20. A draft rigging comprising a housing having a tapered bore. two resilient frictional members having helical edges that-cooperate to expand the resilient members into frictional engagement with the bore of the housing when'they are moved into the housing and means for restorinvl the frictionaly members to their initial positions..

21. A draft rigging comprising a housing having a kfrictional surface, constantly engaged resilient frictional members to cooperate therewith, said frictional members being of substantially split cylinders having their engaging surfaces of such pitch that lateral movement thereof expands the same to eifect frictional engagement with the friotion'al surface of the housing, and means for restoring thefrictional members to their initial positions.

22 A draft rigging comprising a housing having a frictional surface, constantly engaged resilient frictional members' to cooperate therewith, the frictionai members having engaging surfaces of such pitch that lateral movement thereof expands the same to effect frictional engagement with the frictional surface ofthe housing, and resilient means for restoring the frictional members to their initial positions. g

23. A draft rigging comprising a housing having a frictional surface, two oppositely disposed tapered frictional members co-operating therewith, a oating member within the frictional members,a spring disposed on each side of the floating member, said floating member being adapted to permit one of the springs to be compressed a predetermined amount only and to transmit any further forces directly to the other spring.

24. A draft rigging comprising a housing having a frictional surface, two oppositely disposed tapered frictional members oo-operating therewith, a floating member within the frictional members, a spring disposed on eac-h side of the iioating member, said ioating member being adapted to permit one of the springs to be compressed a predetermined amount which is less than the amount that spring is ordinarily capable of being compressed. n Y

In testimony whereof, I have hereunto subscribed my name this 4th day of June, 1920. v

' VVVAL'IKER M. AUSTIN. 

